Why does the mobile menu pop up at resolutions from 991 to 768? how to fix?

Question

css

verstka.vetov.ru/yunika/index.html
If you resize the browser window, you can see that at a resolution of 991 to 768 a mobile menu appears.
And it should be from 768 only.
I can't figure out where I screwed up

Answer 1

bootstrap.css:

.collapse {
  display: none;
}
...
@media (min-width: 992px) {
...
  .navbar-collapse.collapse {
     display: block !important;
      ...
  }
}